The invention relates to a mixture preparation apparatus having a throttle device and a vane body in the air intake line provided with a rotatable scoop, with the scoop arranged to extend into a widened section of the air intake line during increased air flow. A mixture preparation apparatus is already known in which flow rates which are sufficient to cause a rotation of a vane body disposed across the flow direction in the air intake line, with the fuel delivery into the air intake line taking place upstream of the vane body, first arise when the air throughputs are high. The rotary speed of the vane body and thus the resultant loss increase as the air throughputs increase.